Polonium-210 (210Po) is naturally present at trace levels in the environment as a part of the uranium-238 (238U) decay chain. It is typically considered as one of the most radiotoxic nuclides: only one microgram of this alpha emitter (t1/2=138 d) may be sufficient to be fatal to an average adult, making it around 250000 times more toxic than hydrogen cyanide1,2. Due to its toxicological properties, studies have been done to determine 210Po in a variety of samples such as soils, sediments, water, food, tobacco leaves, cigarettes, urine, and biological materials3-12.
Polonium (Po) samples for alpha counting are typically prepared by spontaneous plating on metallic discs. Although silver discs have typically been used for Po plating13, nickel, copper, and stainless steel discs may also be employed due to their lower costs14,45. Prior to being used, the metallic discs are typically polished and cleaned to remove the dust and the oxide layer at the surface16. They are then typically brought in contact with the sample in a minimum volume of diluted HCl solution (typically about 0.1 to 1 M) and agitated for about 3-6 hours at a higher temperature (e.g., 80-95° C.) to obtain the highest yields possible (typically about 90%)8,13-16. The metallic discs are typically subsequently rinsed with water17 and heated at relatively high temperatures (typically about 300° C.) for few minutes to oxidize the polonium and reduce the risk of contamination to the alpha detector15. Although this sample preparation technique is widely performed, this technique, in particular the heating step, may be inconvenient and time consuming. In addition, the plating is typically performed using in-house assemblies resulting in a low analysis throughput.